The present invention relates generally to the art of coarse screening and more particularly to an apparatus for separating the bark from a debarking process and other wood waste according to size.
In the manufacture of paper, it is the normal practice to remove the bark and dirt from the wood raw material before pulping. This is an important step because bark has little or no value as a paper making material. Moreover, if bark is left on the wood raw material, it tends to increase the consumption of chemicals used in the pulping process, thus indirectly raising power costs, and if not adequately digested, may find its way into the paper produced as dark brown specks. On the other hand, bark is an important and useful raw material for other applications. For instance, some barks are rich in tannins which can be used to improve the properties of certain plastics. Also, bark contains some bast fibers which are useful in the manufacture of cork. Meanwhile, the fuel value of bark and other wood waste is quite high, and with the increasing trends toward the integration of pulping and lumbering operations, the need for an efficient and economical means for handling and using bark and other wood waste as a fuel source is important.